I was excited to write about a recent study showing no survival difference between African Americans and white Americans with lung cancer. While most studies seem to suggest that lung cancer survival rates are lower in black people, this new study - one conducted with patients in the military health system - found no significant differences. Hence, one factor that may play a role in survival discrepancies could be access to health care. And the conclusion of that thought is awesome. Equal access to health care may mend the survival discrepancies between different races.
But another theory, published in the journal Dermato-Endocriniology, may also explain some of the differences. A lack of Vitamin D. And unlike some possible causes of the discrepancy, this is something that is fairly easy (relatively speaking anyway) to address.
Given that racial disparities in cancer survival have been found in 13 types of cancer, including lung cancer, after accounting for things such as socioeconomic status, stage at diagnosis, and treatment - - and that there are links between vitamin D level concentrations and survival in all of these cancers, researchers set out to determine if a lack of vitamin D may be responsible for racial differences in cancer survival rates.
And it could be the case. They found that African Americans had serum 25 hydroxyvitamin D levels that were 40% lower than white Americans.
Does this make sense?
Dark skin results in less production of vitamin D from sun exposure. Stated in another way, people with darker complexions require greater amounts of time in the sun to absorb the UVB rays that result in vitamin D production by the body. And the sun is a very significant source of vitamin D.
But what about diet? Don't we get vitamin D in our food? If you do a little math, it becomes clearer. The recommended daily allowance of vitamin D is 600 IU's for men and women aged 19 to 71, though some scientists believe higher levels than this are needed for cancer prevention and prevention of cancer recurrence. An average glass of milk grants us 100 IU's. Added up: to get the minimum recommended dose of vitamin D by dietary measures alone would require drinking 6 glasses of milk (and perhaps eating a little salmon) every day.
What can you do with this information?
A simple blood test can determine your level of vitamin D and whether or not you are deficient. As a side note, it's important to ask not just if your level is normal, but where your level falls in the range. An example here is one of my sons. He has a medical condition in which vitamin D is important in maintaining optimum health. After his blood was drawn, the nurse told me "its normal." When I questioned further, she again said it was normal. When I asked specifically what the number was she said 31. "Only" 31, with a scale of 30 to 80 being normal. Thankfully his physician had let me know that our goal was to have his level at least 50, and advised a supplement of vitamin D3.
It's important to talk with your oncologist about any and all supplements you use, including vitamin D. If your vitamin D level is low, no matter your skin color, ask her what her recommendation are for getting your level back to a level she believes would be best for your optimum health - and maybe even - survival.
Photo: flickr.com, author aafromaa
Source:
Grant, W., and A. Peiris. Differences in vitamin D status may account for unexplained disparities in cancer survival rates between African and White Americans. Dermato-Endocrinology. Volume 4, Issue 2. April/May/June 2012.
So true. In fact according to data from the National Health and Nutrition Examination Survey (NHANES), African Americans are ten times more likely to suffer from extreme vitamin D deficiency (serum levels of 25(OH)D less than 17 ng/ml) then whites.
Skin area exposed also plays a huge role in vitamin D photosynthesis, so seasonal changes in external temperature and fog and cloud cover also come into play.
When a person’s shadow is longer than they are tall, that is generally an indication that no vitamin D photosynthesis is possible, since UVB is filtered out at these lower solar angles due to the longer optical depth.
Other atmospheric factors like stratospheric ozone thickness and certain tropospheric air pollutants, most notably sulfur dioxide, also interfere with UVB transmission.
From a behavioral standpoint, the main variable is the amount of skin surface area exposed. People with darker skin pigmentation will have a more difficult time making vitamin D during winter and require longer exposure in summer. These patients may experience even more profound seasonal low points.
Our group currently recommend that people have their serum 25(OH)D checked twice annually around the end of August (high point) and beginning of March (generally the low point or nadir).
If serum 25(OH)D test is around 20 ng/ml, which is about the national average, it would be good to consider a supplement of 4,000 IU per day to get your level closer to 60 ng/ml.